In X-ray fluoroscopic systems including an X-ray fluoroscopic system for industrial use, X-ray camera (two-dimensional X-ray detector) is disposed so as to face an X-ray source, and an X-ray fluoroscoped image of an object of fluoroscopy such as a sample placed between them is displayed or captured.
In X-ray fluoroscopic systems including an X-ray fluoroscopic system for industrial use, a combination of an image intensifier and a CCD camera or a two-dimensional X-ray detector that is made up of an FPD (flat panel detector) (in this specification, they are generally referred to as an X-ray camera) is disposed so as to face the X-ray source, and an X-ray fluoroscoped image of the object of fluoroscopy such as a sample placed between them is captured by the X-ray camera.
In this type of X-ray fluoroscopic system, an XY table for positioning the object of fluoroscopy is usually disposed between the X-ray source and the X-ray camera such that an arbitrary observed point (viewpoint) on the object of fluoroscopy comes within the field of view of the X-ray camera.
Further, some of this type of X-ray fluoroscopic systems is equipped with a tilting mechanism that tilts the X-ray camera to the optical axis center of the X-ray source, and furthermore, a system equipped with a rotating mechanism that relatively rotates the X-ray camera and the XY table around an axis orthogonal to the XY table is also practically used.
Meanwhile, in the X-ray fluoroscopic system equipped with the tilting mechanism, in the state where a desired observed point of the object of fluoroscopy is within the field of view of the X-ray camera by driving the XY table, when the X-ray camera is tilted by the tilting mechanism to allow the observed point to be fluoroscoped from different angles, the observed point comes off from the field of view of the X-ray camera, and it becomes necessary to manually operate the XY table to track the point. Particularly, in the case of performing work at high magnifying power, it is extremely difficult to manually operate the XY table to track the observed point. Further, in the X-ray fluoroscopic system equipped with the rotating mechanism as well, there are cases where the observed point comes off from the field of view of the X-ray camera while moving in an arc shape due to rotation, and it is difficult to track the point while manually operating the XY table.